The 737 was originally envisioned in 1964. The initial 737-100 made its first flight in April 1967, and entered airline service in February 1968 with Lufthansa.[4][5] Next, the lengthened 737-200 entered service in April 1968. In the 1980s Boeing launched the longer 737-300, −400, and −500 variants (referred to as the Boeing 737 Classic series) featuring CFM56turbofan engines and wing improvements.

The Boeing 737 Next Generation (NG) was introduced in the 1990s, with a redesigned, increased span wing, upgraded "glass" cockpit, and new interior. The 737 NG comprises the 737-600, −700, −800, and −900 variants, with lengths ranging from 31.09 to 42.06 m (102 to 138 ft). Boeing Business Jet versions of the 737 NG are also produced. The 737 was revised again in the 2010s for greater efficiency, with the 737 MAX series featuring CFM LEAP-1B engines and improved winglets. The 737 MAX entered service in 2017.

The 737 series is the highest-selling commercial jetliner in history.[4] The 737 has been continuously manufactured since 1967; the 10,000th was rolled out on March 13, 2018, a MAX 8 destined for Southwest Airlines, and over 4,600 orders are pending.[6] Assembly of the 737 is performed at the Boeing Renton Factory in Renton, Washington. Many 737s serve markets previously filled by 707, 727, 757, DC-9, and MD-80/MD-90 airliners, and the aircraft currently competes primarily with the Airbus A320 family.[7] As of 2006, there were an average of 1,250 Boeing 737s airborne at any given time, with two either departing or landing somewhere every five seconds.[8]

Boeing had been studying short-haul jet aircraft designs, and wanted to produce another aircraft to supplement the 727 on short and thin routes.[9] Preliminary design work began on May 11, 1964,[10] and Boeing's intense market research yielded plans for a 50- to 60-passenger airliner for routes 50 to 1,000 mi (100 to 1,600 km) long.[9][11]

Initial design featured podded engines on the aft fuselage and a T-tail like the 727, and five-abreast seating, but engineer Joe Sutter instead placed the engines under the wings to lighten the structure, enabling fuselage widening for six-abreast seating.[12] The 737 design was presented in October 1964 at the Air Transport Association maintenance and engineering conference by chief project engineer Jack Steiner, where its elaborate high-lift devices raised concerns about maintenance costs and dispatch reliability.[12] The launch decision for the $150 million development was made by the board on February 1, 1965.[12]

Lufthansa became the launch customer on February 19, 1965,[13] with an order for 21 aircraft, worth $67 million[14] in 1965, after the airline received assurances from Boeing that the 737 project would not be canceled.[15] Consultation with Lufthansa over the previous winter resulted in an increase in capacity to 100 seats.[13]

On April 5, 1965, Boeing announced an order by United Airlines for 40 737s. United wanted a slightly larger airplane than the original 737, so Boeing stretched the fuselage 36 in (91 cm) ahead of, and 40 in (102 cm) behind the wing.[16] The longer version was designated 737-200, with the original short-body aircraft becoming the 737-100.[17]

Detailed design work continued on both variants at the same time. Boeing was far behind its competitors when the 737 was launched; rival aircraft BAC-111, Douglas DC-9, and Fokker F28 were already into flight certification.[14] To expedite development, Boeing used 60% of the structure and systems of the existing 727, the most notable being the fuselage cross-section. This fuselage permitted six-abreast seating compared to the rival BAC-111 and DC-9's five-abreast layout.[13]

Design engineers decided to mount the nacelles directly to the underside of the wings to reduce the landing gear length and kept the engines low to the ground for easy ramp inspection and servicing.[18] Many thickness variations for the engine attachment strut were tested in the wind tunnel and the most desirable shape for high speed was found to be one which was relatively thick, filling the narrow channels formed between the wing and the top of the nacelle, particularly on the outboard side.

Originally, the span arrangement of the airfoil sections of the 737 wing was planned to be very similar to that of the 707 and 727, but somewhat thicker. A substantial improvement in drag at high Mach numbers was achieved by altering these sections near the nacelle.[19] The engine chosen was the Pratt & Whitney JT8D-1 low-bypass ratio turbofan engine, delivering 14,500 lbf (64 kN) thrust.[20] With the wing-mounted engines, Boeing decided to mount the horizontal stabilizer on the fuselage rather than the T-tail style of the Boeing 727.[16]

The initial assembly of the Boeing 737 was adjacent to Boeing Field (now officially named King County International Airport) because the factory in Renton was filled to capacity with the production of the 707 and 727. After 271 of the Boeing 737 aircraft were built, production was moved to Renton in late 1970.[15][21] A significant portion of fuselage assembly—previously done by Boeing in Wichita, Kansas—is now performed by Spirit AeroSystems, which purchased some of Boeing's assets in Wichita.[22][23]
Key to increasing production efficiencies, the entire fuselage is shipped since the 737 Next Generation while it was sent in two pieces before.[24]

The fuselage is joined with the wings and landing gear and then moves down the assembly line for the engines, avionics, and interiors. After rolling out the aircraft, Boeing tests the systems and engines before a plane's maiden flight to Boeing Field, where it is painted and fine-tuned before delivery to the customer.[25] The first of six -100 prototypes rolled out in December 1966 and made its maiden flight on April 9, 1967, piloted by Brien Wygle and Lew Wallick.[26] On December 15, 1967, the Federal Aviation Administration certified the 737-100 for commercial flight,[27] issuing Type Certificate A16WE.[28] The 737 was the first aircraft to have, as part of its initial certification, approval for Category II approaches,[29] which refers to an precision instrument approach and landing with a decision height between 98 to 197 feet (30 to 60 m).[30]

Lufthansa received its first aircraft on December 28, 1967. On February 10, 1968, Lufthansa became the first non-American airline to launch a new Boeing aircraft.[27]Lufthansa was the only significant customer to purchase the 737-100. Only 30 aircraft were produced.[31]

The 737-200 had its maiden flight on August 8, 1967. It was certified by the FAA on December 21, 1967,[28][32] and the inaugural flight for United was on April 28, 1968, from Chicago to Grand Rapids, Michigan.[27] The lengthened -200 was widely preferred over the -100 by airlines.[33]

Sales were low in the early 1970s and, after a peak of 114 deliveries in 1969, only 22 737s were shipped in 1972 with 19 in backlog. The US Air Force saved the program by ordering T-43s. African airline orders kept the production running until the 1978 US Airline Deregulation Act where demand was better for a six-abreast narrow-body aircraft, particularly re-engined with the CFM56, struggling at the time.[12]

An early-production, retrofitted United Airlines 737-200 with deployed thrust reversers

The original engine nacelles incorporated thrust reversers taken from the 727 outboard nacelles. They proved to be relatively ineffective and tended to lift the aircraft up off the runway when deployed. This reduced the downforce on the main wheels thereby reducing the effectiveness of the wheel brakes. In 1968, an improvement to the thrust reversal system was introduced.[34] A 48-inch tailpipe extension was added and new, target-style, thrust reversers were incorporated. The thrust reverser doors were set 35 degrees away from the vertical to allow the exhaust to be deflected inboard and over the wings and outboard and under the wings.[35] The improvement became standard on all aircraft after March 1969, and a retrofit was provided for active aircraft. Boeing fixed the drag issue by introducing new longer nacelle/wing fairings, and improved the airflow over the flaps and slats. The production line also introduced an improvement to the flap system, allowing increased use during takeoff and landing. All these changes gave the aircraft a boost to payload and range, and improved short-field performance.[27] In May 1971, after aircraft #135, all improvements, including more powerful engines and a greater fuel capacity, were incorporated into the 737-200, giving it a 15% increase in payload and range over the original -200s.[29] This became known as the 737-200 Advanced, which became the production standard in June 1971.[36]

737-200 planform

In 1970, Boeing received only 37 orders. Facing financial difficulties, Boeing considered closing the 737 production-line and selling the design to Japanese aviation companies.[15] After the cancellation of the Boeing Supersonic Transport, and scaling back of 747 production, enough funds were freed up to continue the project.[37] In a bid to increase sales by offering a variety of options, Boeing offered a 737C (Convertible) model in both -100 and -200 lengths. This model featured a 134 in × 87 in (340 cm × 221 cm) freight door just behind the cockpit, and a strengthened floor with rollers, which allowed for palletized cargo. A 737QC (Quick Change) version with palletized seating allowed for faster configuration changes between cargo and passenger flights.[38] With the improved short-field capabilities of the 737, Boeing offered the option on the -200 of the gravel kit, which enables this aircraft to operate on remote, unpaved runways.[39][40] Until retiring its -200 fleet in 2007, Alaska Airlines used this option for some of its combi aircraft rural operations in Alaska.[41] Northern Canadian operators Air Inuit, Air North, Canadian North, First Air and Nolinor Aviation still operate the gravel kit aircraft in Northern Canada, where gravel runways are common.

In 1988, the initial production run of the -200 model ended after producing 1,114 aircraft. The last one was delivered to Xiamen Airlines on August 8, 1988.[42][43]

Development began in 1979 for the 737's first major revision. Boeing wanted to increase capacity and range, incorporating improvements to upgrade the aircraft to modern specifications, while also retaining commonality with previous 737 variants. In 1980, preliminary aircraft specifications of the variant, dubbed 737-300, were released at the Farnborough Airshow.[44]

The 737-300 was the first Classic variant

Boeing engineer Mark Gregoire led a design team, which cooperated with CFM International to select, modify and deploy a new engine and nacelle that would make the 737-300 into a viable aircraft. They chose the CFM56-3B-1high-bypassturbofan engine to power the aircraft, which yielded significant gains in fuel economy and a reduction in noise, but also posed an engineering challenge, given the low ground clearance of the 737 and the larger diameter of the engine over the original Pratt & Whitney engines. Gregoire's team and CFM solved the problem by reducing the size of the fan (which made the engine slightly less efficient than it had been forecast to be), placing the engine ahead of the wing, and by moving engine accessories to the sides of the engine pod, giving the engine a distinctive non-circular "hamster pouch"[45] air intake.[46][47] Earlier customers for the CFM56 included the U.S. Air Force with its program to re-engine KC-135 tankers.[48]

The passenger capacity of the aircraft was increased to 149 by extending the fuselage around the wing by 9 feet 5 inches (2.87 m). The wing incorporated several changes for improved aerodynamics. The wingtip was extended 9 in (23 cm), and the wingspan by 1 ft 9 in (53 cm). The leading-edge slats and trailing-edge flaps were adjusted.[46] The tailfin was redesigned, the flight deck was improved with the optional EFIS (Electronic Flight Instrumentation System), and the passenger cabin incorporated improvements similar to those developed on the Boeing 757.[49] The prototype −300, the 1,001st 737 built, first flew on February 24, 1984 with pilot Jim McRoberts.[49] It and two production aircraft flew a nine-month-long certification program.[50]

In June 1986, Boeing announced the development of the 737-400,[51] which stretched the fuselage a further 10 ft (3.0 m), increasing the passenger load to 188.[52] The -400s first flight was on February 19, 1988, and, after a seven-month/500-hour flight-testing run, entered service with Piedmont Airlines that October.[53]

Transaero 737-400 at takeoff. The stubbier CFM56 engines are mounted ahead of the wings.

The -500 series was offered, due to customer demand, as a modern and direct replacement of the 737-200. It incorporated the improvements of the 737 Classic series, allowing longer routes with fewer passengers to be more economical than with the 737-300. The fuselage length of the -500 is 1 ft 7 in (48 cm) longer than the 737-200, accommodating up to 140[52] passengers. Both glass and older-style mechanical cockpits arrangements were available.[53] Using the CFM56-3 engine also gave a 25% increase in fuel efficiency over the older -200s P&W engines.[53]

The 737-500 was launched in 1987 by Southwest Airlines, with an order for 20 aircraft,[54] and flew for the first time on June 30, 1989.[53] A single prototype flew 375 hours for the certification process,[53] and on February 28, 1990, Southwest Airlines received the first delivery.[55]

After the introduction of the −600/700/800/900 series, the −300/400/500 series was called the 737 Classic series.[56]

The price of jet fuel reached a peak in 2008, when airlines devoted 40% of the retail price of an air ticket to pay for fuel, versus 15% in 2000.[57][58] Consequently, in that year carriers retired Classic 737 series aircraft to reduce fuel consumption; replacements consisted of more efficient Next Generation 737s or Airbus A320/A319/A318 series aircraft. On June 4, 2008, United Airlines announced it would retire all 94 of its Classic 737 aircraft (64 737-300 and 30 737-500 aircraft), replacing them with Airbus A320 jets taken from its Ted subsidiary, which has been shut down.[59][60][61]

Prompted by the new Airbus A320, Boeing initiated development of an updated series of aircraft in 1991.[62] After working with potential customers, the 737 Next Generation (NG) program was announced on November 17, 1993.[63] The 737NG encompasses the -600, -700, -800, and -900, and is to date the most significant upgrade of the airframe. The performance of the 737NG is, in essence, that of a new aircraft, but important commonality is retained from previous 737 models.[64]

Boeing 737NG fuselage being transported by rail

The wing was redesigned with a new airfoil section, greater chord, increased wing span by 16 ft (4.9 m) and area by 25%, which increased total fuel capacity by 30%. New, quieter, more fuel-efficient CFM56-7B engines were used.[65] The wing, engine, and fuel capacity improvements combined increase the 737's range by 900 nautical miles (1,700 km) to over 3,000 nautical miles (5,600 km),[66] now permitting transcontinental service.[63] With the increased fuel capacity, higher maximum takeoff weight (MTOW) specifications are offered. The 737NG included redesigned vertical stabilizers, and winglets were available on most models.[67] The flight deck was upgraded with modern avionics, and passenger cabin improvements similar to those on the Boeing 777, including more curved surfaces and larger overhead bins than previous-generation 737s. The Next Generation 737 interior was also adopted on the Boeing 757-300.[68][69]

The first NG to roll out was a -700, on December 8, 1996. This aircraft, the 2,843rd 737 built, first flew on February 9, 1997. The prototype -800 rolled out on June 30, 1997, and first flew on July 31, 1997. The smallest of the new variants, the -600s, is the same size as the -500. It was the last in this series to launch, in December 1997. First flying January 22, 1998, it was given certification on August 18, 1998.[63][70] A flight test program was operated by 10 aircraft; 3 -600s, 4 -700s, and 3 -800s.[63]

Boeing 737-700 in Air Berlin–Boeing livery, showing blended winglets available on the 737 Next Generation models

In 2004, Boeing offered a Short Field Performance package in response to the needs of Gol Transportes Aéreos, which frequently operates from restricted airports. The enhancements improve takeoff and landing performance. The optional package is available for the 737NG models and standard equipment for the 737-900ER. The CFM56-7B Evolution nacelle began testing in August 2009 to be used on the new 737 PIP (Performance Improvement Package) due to enter service mid-2011. This new improvement is said to shave at least 1% off overall drag and have some weight benefits. Overall, it is claimed to have a 2% improvement on fuel burn on longer stages.[71] In 2010, new interior options for the 737NG included the 787-style Boeing Sky Interior.[71]

Boeing delivered the 5,000th 737 to Southwest Airlines on February 13, 2006, the 6,000th 737 to Norwegian Air Shuttle in April 2009, the 8,000th 737 to United Airlines on April 16, 2014.[72] The Airbus A320 family has outsold the 737NG over the past decade,[73][74][75] although its order totals include the A321 and A318, which have also rivaled Boeing's 757 and 717, respectively.[7] The 737NG has also outsold the A320 on an annual basis in past years,[76][77][78][79][80] with the next generation series extending the jetliner's run as the most widely sold[81][82][83] and commonly flown airliner family since its introduction.[84][85][86][87][88][89] The 10,000th aircraft was ordered in July 2012.[90]

Boeing produces 42 of the type per month in 2015, and expects to increase to 52 per month in 2018.[91] The slow selling 737-600 is no longer being marketed and was removed from the Boeing website as of 2016[update], its position as the smallest model being taken by the more popular 737-700.[92]

Since 2006, Boeing has discussed replacing the 737 with a "clean sheet" design (internally named "Boeing Y1") that could follow the Boeing 787 Dreamliner.[93] A decision on this replacement was postponed, and delayed into 2011.[94] In November 2014, it was reported that Boeing plans to develop a new aircraft to replace the 737 in the 2030 time frame. The airplane is to have a similar fuselage, but probably made from composite materials similar to the Boeing 787 Dreamliner.[95] Boeing also considers a parallel development along with the 757 replacement, similar to the development of the 757 and 767 in the 1970s.[96]

On September 23, 2015, Boeing announced a collaboration with Commercial Aircraft Corporation of China Ltd. to build a completion and delivery facility for the 737 in China, the first outside the U.S.[102][103] This facility initially handles interior finishing only, but will subsequently be expanded to include paintwork. The first 737 MAX was delivered from the facility to Air China on December 15, 2018.[104]

The 737's main landing gear under the wings at mid-cabin rotates into wells in the aircraft's belly. The legs are covered by partial doors, and "brush-like" seals aerodynamically smooth (or "fair") the wheels in the wells. The sides of the tires are exposed to the air in flight. "Hub caps" complete the aerodynamic profile of the wheels. It is forbidden to operate without the caps, because they are linked to the ground speed sensor that interfaces with the anti-skid brake system. The dark circles of the tires are clearly visible when a 737 takes off, or is at low altitude.[105]

As the 737's fuselage design is derived from that of the Boeing 707, it inherited the distinctive 'eyebrow windows' used on the larger airliner, situated just above the windscreen.

737s are not equipped with fuel dump systems. The original aircraft were too small to require them, and adding a fuel dump system to the later, larger variants would have incurred a large weight penalty. Boeing instead demonstrated an "equivalent level of safety". Depending upon the nature of the emergency, 737s either circle to burn off fuel or land overweight. If the latter is the case, the aircraft is inspected by maintenance personnel for damage and then returned to service if none is found.[106][107]

Engines on the 737 Classic series (−300, −400, −500) and Next-Generation series (−600, −700, −800, −900) do not have circular inlets like most aircraft. The 737 Classic series featured CFM56turbofan engines, which yielded significant gains in fuel economy and a reduction in noise over the JT8D engines used on the −100 and −200, but also posed an engineering challenge given the low ground clearance of the 737. Boeing and engine supplier CFMI solved the problem by placing the engine ahead of (rather than below) the wing, and by moving engine accessories to the sides (rather than the bottom) of the engine pod, giving the 737 a distinctive non-circular air intake.[46]

The wing also incorporated changes for improved aerodynamics. The engines' accessory gearbox was moved from the 6 o'clock position under the engine to the 4 o'clock position (from a front/forward looking aft perspective). This side-mounted gearbox gives the engine a somewhat triangular rounded shape. Because the engine is close to the ground, 737-300s and later models are more prone to engine foreign object damage (FOD). The improved CFM56-7 turbofan engine on the 737 Next Generation is 7% more fuel-efficient than the previous CFM56-3 in the 737 classics. The newest 737 variants, the 737 MAX family, are to feature CFM International LEAP-1B engines with a 68 inches (1.73 m) fan diameter. These engines are expected to be 10-12% more efficient than the CFM56-7B engines on the 737 Next Generation family.[108]

The primary flight controls are intrinsically safe. In the event of total hydraulic system failure or double engine failure, they will automatically and seamlessly revert to control via servo tab. In this mode, the servo tabs aerodynamically control the elevators and ailerons; these servo tabs are in turn controlled by cables running to the control yoke. The pilot's muscle forces alone control the tabs. For the 737 Next Generation, a six-screen LCD glass cockpit with modern avionics was implemented while retaining crew commonality with previous generation 737.[109]

Most 737 cockpits were delivered with "eyebrow windows" positioned above the main glareshield, which were a feature of the original 707 and 727[110] to allow for better crew visibility.[111] Contrary to popular belief, these windows were not intended for celestial navigation[112] (only the military T-43A had a sextant port for star navigation, which the civilian models lacked[113]). With modern avionics, the windows became redundant, and many pilots actually placed newspapers or other objects in them to block out sun glare. They were eliminated from the 737 cockpit design in 2004, although they are still installed on customer request.[114] The eybrow windows are sometimes removed and plugged, usually during maintenance overhauls, and can be distinguished by the metal plug which differs from the smooth metal in later aircraft that were not originally fitted with the windows.[114]

The 737 has four different winglet types: 737-200 Mini-winglet, 737 Classic/NG Blended Winglet, 737 Split Scimitar Winglet, and 737 MAX Advanced Technology Winglet.[114] The 737-200 Mini-winglets are part of the Quiet Wing Corp modification kit that received certification in 2005.[114]

Blended winglets are in production on 737 NG aircraft and are available for retrofit on 737 Classic models. These winglets stand approximately 8 feet (2.4 m) tall and are installed at the wing tips. They help to reduce fuel burn (by reducing vortex drag), engine wear, and takeoff noise. Overall fuel efficiency improvement is up to five percent through the reduction of lift-induced drag.[115][116]

Split Scimitar winglets became available in 2014 for the 737-800, 737-900ER, BBJ2 and BBJ3, and in 2015 for the 737-700, 737-900 and BBJ1.[117] Split Scimitar winglets were developed by Aviation Partners Inc. (API), the same Seattle based corporation that developed the blended winglets; the Split Scimitar winglets produce up to a 5.5% fuel savings per aircraft compared to 3.3% savings for the blended winglets. Southwest Airlines flew their first flight of a 737-800 with Split Scimitar winglets on April 14, 2014.[118] The next generation 737, 737 MAX, will feature an Advanced Technology (AT) Winglet that is produced by Boeing. The Boeing AT Winglet resembles a cross between the Blended Winglet and the Split Scimitar Winglet.[119]

As of July 2008[update] the 737 features carbon brakes manufactured by Messier-Bugatti. These new brakes, now certified by the Federal Aviation Administration, weigh 550–700 lb (250–320 kg) less than the steel brakes normally fitted to the Next-Gen 737s (weight savings depend on whether standard or high-capacity brakes are fitted).[120] A weight reduction of 700 pounds on a Boeing 737-800 results in 0.5% reduction in fuel burn.[121]

A short-field design package is available for the 737-600, -700, and -800, allowing operators to fly increased payload to and from airports with runways under 5,000 feet (1,500 m). The package consists of sealed leading edge slats (improved lift), a two-position tail skid (enabling greater protection against tail strikes that may be caused by the lower landing speeds), and increased flight spoiler deflection on the ground. These improvements are standard on the 737-900ER.[122]

The 737 interior arrangement has changed in successive generations. The original 737 interior was restyled for the 737 Classic models using 757 designs, while 777 architecture was used for the debut of the Next Generation 737. Designed using Boeing's new cabin concepts, the latest Sky Interior features sculpted sidewalls and redesigned window housings, along with increased headroom and LED mood lighting.[71][123] Larger pivot-bins similar to those on the 777 and 787 have more luggage space than prior designs.[123] The Sky Interior is also designed to improve cabin noise levels by 2–4 dB.[71] The first 737 equipped with the Boeing Sky Interior was delivered to Flydubai in late 2010.[71] Continental Airlines,[124][125]Alaska Airlines,[126]Malaysia Airlines,[127] and TUIFly have also received Sky Interior-equipped 737s.[128]

The 737 models can be divided into four generations, including thirteen major variants. The "Original" models consist of the 737-100, 737-200/-200 Advanced. The "Classic" models consist of the 737-300, 737-400, and 737-500. The "Next Generation" variants consist of the 737-600, 737-700/-700ER, 737-800, and 737-900/-900ER. Of these variants, many feature additional versions such as the T-43, which was a modified Boeing 737-200 used by the United States Air Force (USAF). The fourth generation derivative - the 737 MAX - consists of the 737-MAX-7, 737-MAX-8, and 737-MAX-9 which will replace the -700, -800 and -900/900ER versions of the NG family, respectively. A fourth MAX variant, the 737-MAX-10 is currently under development and is the largest 737 to date.

The initial model was the 737-100. It was launched in February 1965. The -100 was rolled out on January 17, 1967, had its first flight on April 9, 1967 and entered service with Lufthansa in February 1968. The aircraft is the smallest variant of the 737. A total of 30 737-100s were ordered and delivered; the final commercial delivery took place on October 31, 1969 to Malaysia–Singapore Airlines. No 737-100s remain in commercial service. The original Boeing prototype, last operated by NASA and retired more than 30 years after its maiden flight, is on exhibit in the Museum of Flight in Seattle.[63]

The 737-200 is a 737-100 with an extended fuselage, launched by an order from United Airlines in 1965. The -200 was rolled out on June 29, 1967, and entered service with United in April 1968. The 737-200 Advanced is an improved version of the -200, introduced into service by All Nippon Airways on May 20, 1971.[129] The -200 Advanced has improved aerodynamics, automatic wheel brakes, more powerful engines, more fuel capacity, and longer range than the -100.[130] Boeing also provided the 737-200C (Cargo), which allowed for conversion between passenger and cargo use and the 737-200QC (Quick Change), which facilitated a rapid conversion between roles. The 1,095th and last delivery of a -200 series aircraft was in August 1988 to Xiamen Airlines.[1][64]

With a gravel kit modification the 737-200 can use unimproved or unpaved landing strips, such as gravel runways, that other similarly-sized jet aircraft cannot. Gravel-kitted 737-200 Combis are currently used by Canadian North, First Air, Air Inuit, Nolinor and Air North in northern Canada. For many years, Alaska Airlines made use of gravel-kitted 737-200s to serve Alaska's many unimproved runways across the state.[131]

Nineteen 737-200s, designated T-43, were used to train aircraft navigators for the U.S. Air Force. Some were modified into CT-43s, which are used to transport passengers, and one was modified as the NT-43A Radar Test Bed. The first was delivered on July 31, 1973 and the last on July 19, 1974. The Indonesian Air Force ordered three modified 737-200s, designated Boeing 737-2x9 Surveiller. They were used as Maritime reconnaissance (MPA)/transport aircraft, fitted with SLAMMAR (Side-looking Multi-mission Airborne Radar). The aircraft were delivered between May 1982 and October 1983.[132]

Many 737-200s have been phased out or replaced by newer 737 versions. After 40 years, in March 2008, the final 737-200 aircraft in the U.S. flying scheduled passenger service were phased out, with the last flights of Aloha Airlines.[133] The variant still sees regular service through North American charter operators such as Sierra Pacific.[134]

In July 2018, there were a combined 58 Boeing 737-200s in service, mostly with "second and third tier" airlines, and those of developing nations.[134]

The Boeing 737 Classic is the name given to the -300/-400/-500 series of the Boeing 737 after the introduction of the -600/700/800/900 series. The Classic series was originally introduced as the 'new generation' of the 737.[135] Produced from 1984 to 2000, 1,988 aircraft were delivered.[55]

By the early 1990s, it became clear that the new Airbus A320 was a serious threat to Boeing's market share, as Airbus won previously loyal 737 customers such as Lufthansa and United Airlines. In November 1993, Boeing's board of directors authorized the Next Generation program to replace the 737 Classic series. The -600, -700, -800, and -900 series were planned.[136] After engineering trade studies and discussions with major 737 customers, Boeing proceeded to launch the 737 Next Generation series in late 1993, with 6,996 built as of January 2019[update].[1] Variants include the P-8 Poseidon.

The 737 MAX is based on earlier 737 designs. The MAX is re-engined with more efficient CFM International LEAP-1B powerplants, aerodynamic improvements (most notably split-tip winglets), and airframe modifications. The 737 MAX series is offered in four lengths, typically offering 138 to 230 seats and a 3,215 to 3,825 nmi (5,954 to 7,084 km) range. The 737 MAX 7, MAX 8, and MAX 9 replace, respectively, the 737-700, -800, and -900. Additional length is offered with the further stretched 737 MAX 10. As of January 2019[update], the Boeing 737 MAX has received 5,011 firm orders.[1]

The Boeing Business Jet is a customized version of the 737. Plans for a business jet version of the 737 are not new. In the late 1980s, Boeing marketed the 77-33 jet, a business jet version of the 737-300.[143] The name was short-lived. After the introduction of the next generation series, Boeing introduced the Boeing Business Jet (BBJ) series. The BBJ1 was similar in dimensions to the 737-700 but had additional features, including stronger wings and landing gear from the 737-800, and had increased range (through the use of extra fuel tanks) over the other 737 models. The first BBJ rolled out on August 11, 1998 and flew for the first time on September 4.[144]

On October 11, 1999 Boeing launched the BBJ2. Based on the 737-800, it is 19 feet 2 inches (5.84 m) longer than the BBJ, with 25% more cabin space and twice the baggage space, but has slightly reduced range. It is also fitted with auxiliary belly fuel tanks and winglets. The first BBJ2 was delivered on February 28, 2001.[144]

Boeing's BBJ3 is based on the 737-900ER. The BBJ3 has 1,120 square feet (104 m2) of floor space, 35% more interior space, and 89% more luggage space than the BBJ2. It has an auxiliary fuel system, giving it a range of up to 4,725 nautical miles (8,751 km), and a Head-up display. Boeing completed the first example in August 2008. This aircraft's cabin is pressurized to a simulated 6,500-foot (2,000 m) altitude.[145][146]

Boeing is studying plans to offer passenger to freighter conversion for the 737-800. Boeing has signed an agreement with Chinese YTO Airlines to provide the airline with 737-800 Boeing Converted Freighters (BCFs) pending a planned program launch.[147] In 2016, Boeing officially launched the 737-800BCF program, converting old passenger jets to dedicated freighters.[148] The first aircraft was delivered in 2018 to GECAS, which is leased to West Atlantic.[149]

In March 2018, the 10,000th 737 was rolled out as over 4,600 orders are pending.[6]
The 737 is operated by more than 500 airlines, flying to 1,200 destinations in 190 countries: over 4,500 are in service and at any given time there are on average 1,250 airborne worldwide. On average, somewhere in the world, a 737 took off or landed every five seconds in 2006.[8] Since entering service in 1968, the 737 has carried over 12 billion passengers over 74 billion miles (120 billion km; 65 billion nm), and has accumulated more than 296 million hours in the air. The 737 represents more than 25% of the worldwide fleet of large commercial jet airliners.[8][150]

The Boeing 737 Classics and the Boeing 737 Next Generation have faced main challenges from the Airbus A320 family introduced in 1988, which was developed to compete also with the McDonnell Douglas MD-80/90 series and the Boeing 717 (formerly named McDonnell Douglas MD-95).

Boeing has delivered over 10,478 aircraft of the 737 family since late 1967,[1] with over 8,900 of those deliveries since March 1, 1988,[152] and has a further 4,754 on firm order as of January 2019[update].[1] In comparison, Airbus has delivered 8,638 A320 series aircraft since their certification/first delivery in early 1988, with another 6,023 on firm order (as of January 2019[update]).[153]

As of February 2019[update], 15,233 units of the Boeing 737 have been ordered, with 4,723 units to be delivered.[1] Units built by model type for 737 Original, Classic, Next Generation, and Boeing Business Jet families are as follows:

An analysis by Boeing on commercial jet airplane accidents in the period 1959–2013 showed that the original series had a hull loss rate of 1.75 per million departures versus 0.54 for the classic series and 0.27 for the Next Generation series.[162]

23660/1294: 737-377 registered G-CELS on static display at Norwich Airport (UK) as an Aviation Academy trainer. It is painted in the silver & red Jet2.com colour scheme, without the logo branding.[181]

^Jiang, Steven. "Jetset: 'Tianjin Takes Off'."The Beijinger. Retrieved: April 22, 2010. Quote: A320, the workhorse of many airlines and the second best-selling jetliner family of all time (after Boeing's venerable B737).

1.
Jet airliner
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A jet airliner is an airliner powered by jet engines. Airliners usually have two or four jet engines, three-engined designs were popular in the 1970s but are common today. Most airliners today are powered by jet engines, because they are capable of operating at high speeds. The first airliners, introduced in the 1950s, used the simpler turbojet engine, these were supplanted by designs using turbofans. Airliners are commonly classified as either the generally long-haul widebody aircraft and they retained the two inboard piston engines, the jets being housed in the outboard nacelles. The first airliner with jet power only was the Nene-powered Vickers VC.1 Viking G-AJPH, also developed in 1949 was the Avro Canada C102 Jetliner, which never reached production, however the term jetliner came into use as a generic term for passenger jet aircraft. National prestige was attached to developing prototypes and bringing these first generation designs into service, there was also a strong nationalism in purchasing policy, so that US Boeing and Douglas aircraft became closely associated with Pan Am, while BOAC ordered British Comets. Aeroflot used Soviet Tupolevs, while Air France introduced French Caravelles, Boeing became the most successful of the early manufacturers. The KC-135 Stratotanker and military versions of the 707 remain operational, the Pratt & Whitney JT3 turbojets powered the original Boeing 707 and DC-8 models, in the early 1960s the JT3 was modified into the JT3D low-bypass turbofan for long-range 707 and DC-8 variants. The second-generation of jet airliners was known for the advancement of turbofan technology, the rear-engined T-tail arrangement is still used for jetliners with a maximum takeoff weight of less than 50 tons. Other second-generation developments, such as rocket assisted takeoff, water-injection, and afterburners used on supersonic jetliners such as Concorde, the third generation of jet airliners introduced wide-body craft and high-bypass turbofan engines. There was also the debut of the European consortium Airbus. In 1978, Boeing unveiled the twin-engine Boeing 757 to replace its 727, the mid-size 757 and 767 launched to market success, due in part to 1980s extended-range twin-engine operational performance standards regulations governing transoceanic twinjet operations. These regulations allowed twin-engine airliners to make ocean crossings at up to three hours distance from emergency diversionary airports, under ETOPS rules, airlines began operating the 767 on long-distance overseas routes that did not require the capacity of larger airliners. By the late 1980s, DC-10 and L-1011 models were approaching retirement age, mcDonnell Douglas were working on the MD-11, a stretched and upgraded successor of the DC-10. Airbus, thanks to the success of its A320 family, developed the medium-range A330 twinjet, in 1988, Boeing began developing what would be the 777 twinjet, using the twin-engine configuration given past design successes, projected engine developments, and reduced-cost benefits. In addition, Boeing also released an update on their 747. Airliner Aviation Business jet Freight aircraft Jet aircraft Wide-body aircraft List of jet airliners

2.
Boeing Commercial Airplanes
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Boeing Commercial Airplanes is a division of The Boeing Company. It designs, assembles, markets, and sells jet airliners and business jets, it also provides product-related maintenance and training to customers worldwide. It operates from headquarters in Renton, Washington, with more than a dozen engineering, manufacturing. BCA includes the assets of the Douglas Aircraft division of the former McDonnell Douglas Corporation, Boeing Canada Boeing Training & Flight Services CDG Jeppesen, formerly Jeppesen Sanderson. Kevin G. McAllister was named President and CEO of Boeing Commercial Airplanes, McAllister is 53 years old and is a former executive at GE Aviation. For all models sold beginning with the Boeing 707 in 1957, all model designations from 707 through 787 have been assigned, leaving 797 as the only 7X7 model name not assigned to a product. Unlike other models, the 787 uses a single digit to designate the series and this convention was followed in the development of the newest version of the 747, the 747-8. The 747 is the model to use both the triple and single-digit designations. Passenger aircraft that are manufactured as passenger aircraft and later converted to freighter configuration by Boeing carry the suffix BCF designating a Boeing converted freighter. The table below lists only airliners from the jet era, the Boeing 707-138B was a shortened-fuselage, long-range model only sold to Qantas. The Boeing 757-200M was a model built for Royal Nepal Airlines. This plane could be converted between passenger and freighter configuration and it was launched by Royal Nepal Airlines in 1986 and delivered two years later. Boeing 747 The Shuttle Carrier Aircraft The Boeing 747 Large Cargo Freighter is a cargo aircraft. The 747SP production resumed nearly four years after the supposedly final 747SP was built and it had a cockpit crew of two instead of the three-crew layout of other 747SPs. Two Boeing VC-25s were built for the US Air Force as Presidential Air Force One transports and this model was a highly modified 747-200B. Boeing was a consultant to Sukhoi on the Russian Regional Jet program that became the Sukhoi Superjet 100 twin-engine narrowbody airliner. Boeing 2707 – supersonic airliner, canceled, Boeing 7J7 – high-efficiency propfan airliner, canceled and may later resume for Y1. Boeing 747-300 Trijet - high-efficiency trijet version of the Boeing 747-200, Boeing New Large Airplane – double-deck jumbo airliner, canceled

3.
Lufthansa
–
It operates services to 18 domestic destinations and 197 international destinations in 78 countries across Africa, the Americas, Asia, and Europe, using a fleet of more than 270 aircraft. Lufthansa is one of the five founding members of Star Alliance, the name of the company is derived from Luft, and Hansa. Combined with its subsidiaries, the group has 656 aircraft, as of February 2016, in 2014, the group carried over 106 million passengers. Lufthansas registered office and corporate headquarters are in Cologne, the main operations base, called Lufthansa Aviation Center, is at Lufthansas primary hub at Frankfurt Airport. The majority of Lufthansas pilots, ground staff, and flight attendants are based there, Lufthansas secondary hub is Munich Airport. Lufthansa was a state-owned enterprise until 1994, in 2014, 60% of Lufthansas shares were held by institutional investors. The remaining 40% were held by individual stock owners, since 1970, Lufthansa has involved its employees in profit sharing, giving them the opportunity to choose between cash and preference shares. When Lufthansa was privatised, employees received more than 3% of its shares, Lufthansa traces its history to 1926 when Deutsche Luft Hansa A. G. was formed in Berlin. DLH, as it was known, was Germanys flag carrier until 1945 when all services were suspended following the defeat of Nazi Germany, West Germany had not yet been granted sovereignty over its airspace, so it was not known when the new airline could become operational. Nevertheless, in 1953 Luftag placed orders for four Convair CV-340s and four Lockheed L-1049 Super Constellations and set up a maintenance base at Hamburg Airport. On 6 August 1954, Luftag acquired the name and logo of the liquidated Deutsche Lufthansa for DM30,000, on 1 April 1955 Lufthansa won approval to start scheduled domestic flights, linking Hamburg, Düsseldorf, Frankfurt, Cologne, and Munich. In August 1958 fifteen Lufthansa 1049Gs and 1649s left Germany each week to Canada, the special status of Berlin meant that Lufthansa was not allowed to fly to either part of Berlin until 1989. Originally thought to be only a matter, the Division of Germany turned out to be long. East Germany tried to establish its own airline in 1955 using the Lufthansa name, but this resulted in a dispute with West Germany. East Germany instead established Interflug as its national airline in 1963, in 1958 Lufthansa ordered four Boeing 707s and started jet flights from Frankfurt to New York City in March 1960. Boeing 720Bs were later bought to back up the 707 fleet, in February 1961 Far East routes were extended beyond Bangkok, Thailand, to Hong Kong and Tokyo. Lagos, Nigeria and Johannesburg, South Africa were added in 1962, Lufthansa introduced the Boeing 727 in 1964 and that May began the Polar route from Frankfurt to Tokyo via Anchorage. In February 1965 the company ordered twenty-one Boeing 737s that went into service in 1968, Lufthansa was the first customer for the Boeing 737 and was one of four buyers of the 737-100s

4.
Southwest Airlines
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Southwest Airlines Co. is a major U. S. airline, the worlds largest low-cost carrier, headquartered in Dallas, Texas. The airline was established in 1967 by Herb Kelleher and adopted its current name in 1971, the airline has more than 53,000 employees as of October 2016 and operates more than 3,900 departures a day during peak travel season. As of 2014, it carried the most domestic passengers of any U. S. airline, as of December 2016, Southwest Airlines had scheduled services to 101 destinations in the United States and eight additional countries. Service to both Grand Cayman and Cincinnati begins June 4,2017, Southwest Airlines has used only Boeing 737s, except for the period from 1979 to 1987 when it leased some Boeing 727-200s from Braniff International Airways. As of January 2016, Southwest is the largest operator of the Boeing 737 worldwide, with over 700 in service, in 1966 Southwest Airlines was founded by Rollin King and Herbert Kelleher, in 1967 it was incorporated as Air Southwest Company. It was not until 1971 that the airline began scheduled flights, the same year the organization adopted the name Southwest Airlines. The expansion of flights started in 1975, to cities throughout Texas, Service to the East and the Southeast started in the 1990s. The company has employed humor in its advertising, the airlines current slogan is Low fares. Instead of a lawsuit, the CEOs for both companies staged an arm wrestling match, a promotional video was created showing the CEOs training for the bout and distributed among the employees and as a video press release along with the video of the match itself. Herb Kelleher lost the match for Southwest, with Stevens Aviation winning the rights to the phrase, kurt Herwald, CEO of Stevens Aviation, immediately granted the use of Just Plane Smart to Southwest Airlines. The net result was both companies having use of the trademark, $15,000 going to charity and good publicity for both companies, Southwest Airlines is the official commercial airline of the Honor Flight Network. Honor Flights are dedicated to bringing aging and ailing veterans to visit the monuments in Washington. The Southwest Airlines headquarters is located on the grounds of Dallas Love Field in the Love Field neighborhood of Dallas, Texas, on September 17,2012, Southwest broke ground on a new Training and Operational Support building. The TOPS Building is across the street from its current headquarters building, the property includes a two-story,100, 000-square-foot operations building that can withstand an EF3 tornado. It also includes a four-story,392, 000-square-foot office and training facility with two levels devoted to each function, the new facilities house 24-hour coordination and maintenance operations, customer support and services, and training. The project was completed in late 2013, with occupancy beginning in 2014, as of December 31,2016, Southwest Airlines has more than 53,000 employees. Gary C. Kelly is Chairman and CEO of Southwest Airlines, Kelly replaced former CEO Jim Parker on July 15,2004 and assumed the title of President on July 15,2008, replacing former President Colleen Barrett. In July 2008, Herb Kelleher resigned his position as Chairman, Colleen Barrett left her post on the Board of Directors and as Corporate Secretary in May 2008 and as President in July 2008

5.
Ryanair
–
Ryanair Ltd. is an Irish low-cost airline headquartered in Swords, a suburb of Dublin, Ireland, with its primary operational bases at Dublin and London Stansted Airports. In 2016, Ryanair was both the largest European airline by scheduled passengers carried, and the busiest international airline by passenger numbers. Ryanair operates over 370 Boeing 737-800 aircraft, with a single 737-700 used primarily as a charter aircraft, the airline has been characterised by its rapid expansion, a result of the deregulation of the aviation industry in Europe in 1997 and the success of its low-cost business model. Ryanairs route network serves 34 countries in Europe, Africa, since its establishment in 1984, Ryanair has grown from a small airline flying the short journey from Waterford to London into Europes largest carrier. As of 2013 including over 1,200 pilots, after the rapidly growing airline went public in 1997, the money raised was used to expand the airline into a pan-European carrier. Revenues have risen from €231 million in 1998, to €1,843 million in 2003, similarly net profits have increased from €48 million to €339 million over the same period. Ryanair was founded in 1984 as Danren Enterprises by Christopher Ryan, Liam Lonergan and Irish businessman Tony Ryan, in 1986, the company added a second route – flying Dublin–Luton in direct competition with the Aer Lingus / British Airways duopoly for the first time. Under partial EU deregulation, airlines could begin new international intra-EU services, the Irish government at the time refused its approval, to protect Aer Lingus, but Britain, under Margaret Thatchers deregulating Conservative government, approved the service. With two routes and two planes, the airline carried 82,000 passengers in one year. In 1986 the directors of Ryanair took an 85% stake in London European Airways, from 1987 this provided a connection with the Luton Ryanair service onward to Amsterdam, in 1988 London European operated as Ryanair Europe and later began to operate charter services. Ryanair passenger numbers continued to increase, but the airline generally ran at a loss and, Michael OLeary was charged with the task of making the airline profitable. OLeary quickly decided that the key to profitability was low fares, quick turn-around times for aircraft, no frills and no business class, in 1989, a Short Sandringham was operated with Ryanair sponsorship titles but never flew revenue-generating services for the airline. He competed with the airlines by providing a no-frills, low-cost service. Flights were scheduled into regional airports, which offered lower landing and handling charges than larger established international airports, OLeary as Chief Executive took part in a publicity stunt, where he helped out with baggage handling on Ryanair flights at Dublin Airport. By 1995, after the consistent pursuit of its low-cost business model, in 1998, flush with new capital, the airline placed a massive US$2 billion order for 45 new Boeing 737-800 series aircraft. The airline launched its website in 2000, with online booking initially said to be a small, increasingly the online booking contributed to the aim of cutting flight prices by selling directly to passengers and excluding the costs imposed by travel agents. Within a year, the website was handling three-quarters of all bookings, Ryanair launched a new base of operation in Charleroi Airport in 2001. Later that year, the airline ordered 155 new 737-800 aircraft from Boeing at what was believed to be a substantial discount, to be delivered over eight years from 2002 to 2010

6.
United Airlines
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United Continental Holdings, Inc. commonly referred to as United, is a major American airline headquartered in Chicago, Illinois. It is the worlds third-largest airline when measured by revenue, operates a domestic and international route network. In the late 1920s, just prior to the use of the United Airlines name, The Boeing Company, currently one of the worlds largest aircraft manufacturers, United was previously known as United Air Lines. United is a member of Star Alliance, the worlds largest global airline alliance. Regional service is operated by independent carriers under the brand name United Express and its main competitors are American Airlines, Delta Air Lines, and Southwest Airlines. United operates out of nine airline hubs located in Chicago, Denver, Guam, Houston, Los Angeles, Newark, San Francisco, Tokyo and Washington, D. C. Chicago-OHare is Uniteds largest hub, both in terms of passengers carried annually and in terms of departures 181,488 in 2016) and this passed George Bush Intercontinental in Houston, which carried 15.5 million with 178,019 departures. The company employs over 86,000 people while maintaining its headquarters in Chicagos Willis Tower, through the airlines parent company, United Continental Holdings, it is publicly traded under NYSE, UAL with a market capitalization of over $18 billion as of September 2014. United operates maintenance bases in Cleveland and Orlando in addition to the maintenance locations located at Uniteds hubs, United Airlines traces its roots to the Varney Air Lines air mail service of Walter Varney, who also founded Varney Speed Lines from which Continental Airlines had originated. In 1927, aviation pioneer William Boeing founded his airline Boeing Air Transport to operate the San Francisco to Chicago air mail route, in 1933, United began operating the Boeing 247 airliner. It was able to fly a transcontinental flight in 20 hours, after passage of the Air Mail Act in 1934, UATC separated into United Aircraft, the Boeing Airplane Company and United Air Lines. In 1954 United Airlines became the first airline to purchase modern flight simulators which had visual, sound, purchased for US$3 million from Curtiss-Wright, these were the first of todays modern flight simulators for training of commercial passenger aircraft pilots. United merged with Capital Airlines in 1961 and regained its position as the United States largest airline, in 1968, the company reorganized, creating UAL Corporation, with United Airlines as a wholly owned subsidiary. In 1970, the UAL Corporation acquired Western International Hotels, the 1970s also saw economic turmoil, resulting in stagflation and labor unrest. The 1978 Airline Deregulation Act, resulting in industry shakeups, further added to the difficulties in a loss-making period. In 1982, United became the first carrier to operate the Boeing 767, in May 1985, the airline underwent a 29-day pilot strike over managements proposed B-scale pilot pay rates. Making it one of two US carriers permitted exclusive access to Heathrow under Bermuda II until open skies took effect in 2008, the aftermath of the Gulf War and increased competition from low-cost carriers led to losses in 1991 and 1992. In 1995, United became the first airline to introduce the Boeing 777 in commercial service, in 1997, United co-founded the Star Alliance airline partnership

7.
American Airlines
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American Airlines, Inc. commonly referred to as American, is a major American airline headquartered in Fort Worth, Texas. It is the worlds largest airline measured by fleet size, revenue, scheduled passenger-kilometres flown. Regional service is operated by independent and subsidiary carriers under the name of American Eagle. American operates out of ten located in Dallas/Fort Worth, Charlotte, Chicago-OHare, Philadelphia, Miami, Phoenix, Washington, DC-National, Los Angeles, New York-JFK. American operates its primary base at Tulsa International Airport in addition to the maintenance locations located at its hubs. Dallas/Fort Worth International Airport is Americans largest passenger carrying hub handling 51.1 million passengers annually with an average of 140,000 passengers daily, the company as of 2015 employs over 113,300 people. Through the airlines parent company, American Airlines Group, it is traded under NASDAQ. American Airlines was started in 1930 via a union of more than eighty small airlines, the two organizations from which American Airlines was originated were Robertson Aircraft Corporation and Colonial Air Transport. The former was first formed in Missouri in 1921, with both being merged in 1929 into holding company The Aviation Corporation and this in turn, was made in 1930 into an operating company and rebranded as American Airways. In 1934, when new laws and attrition of mail contracts forced many airlines to reorganize, the corporation redid its routes into a connected system, between 1970 and 2000, the company grew into being an international carrier, purchasing Trans World Airlines in 2001. In 2011, due to a downturn in the airline industry, in 2013, US Airways and American Airlines merged. Eventually operations were merged under one operating certificate to create the largest United States airline which kept the American Airlines brand name, American Airlines is headquartered in Fort Worth, Texas, adjacent to the Dallas/Fort Worth International Airport. The headquarters is located in two buildings in the CentrePort office complex and these buildings together have about 1,400,000 square feet of space. As of 2014 over 4,300 employees work at this complex, before it was headquartered in Texas, American Airlines was headquartered at 633 Third Avenue in the Murray Hill area of Midtown Manhattan, New York City. In 1979 American moved its headquarters to a site at Dallas/Fort Worth International Airport, Mayor of New York City Ed Koch described the move as a betrayal of New York City. American moved to two leased office buildings in Grand Prairie, Texas, the airline began leasing the facility from the airport, which owns the facility. As of 2015 American Airlines is the corporation with the largest presence in Fort Worth, in 2015 the airline announced it will build a new headquarters in Fort Worth. Groundbreaking began in the spring of 2016 and occupancy is scheduled for summer 2019, the airline plans to house 5,000 new workers in the building

8.
United States dollar
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The United States dollar is the official currency of the United States and its insular territories per the United States Constitution. It is divided into 100 smaller cent units, the circulating paper money consists of Federal Reserve Notes that are denominated in United States dollars. The U. S. dollar was originally commodity money of silver as enacted by the Coinage Act of 1792 which determined the dollar to be 371 4/16 grain pure or 416 grain standard silver, the currency most used in international transactions, it is the worlds primary reserve currency. Several countries use it as their currency, and in many others it is the de facto currency. Besides the United States, it is used as the sole currency in two British Overseas Territories in the Caribbean, the British Virgin Islands and Turks and Caicos Islands. A few countries use the Federal Reserve Notes for paper money, while the country mints its own coins, or also accepts U. S. coins that can be used as payment in U. S. dollars. After Nixon shock of 1971, USD became fiat currency, Article I, Section 8 of the U. S. Constitution provides that the Congress has the power To coin money, laws implementing this power are currently codified at 31 U. S. C. Section 5112 prescribes the forms in which the United States dollars should be issued and these coins are both designated in Section 5112 as legal tender in payment of debts. The Sacagawea dollar is one example of the copper alloy dollar, the pure silver dollar is known as the American Silver Eagle. Section 5112 also provides for the minting and issuance of other coins and these other coins are more fully described in Coins of the United States dollar. The Constitution provides that a regular Statement and Account of the Receipts and that provision of the Constitution is made specific by Section 331 of Title 31 of the United States Code. The sums of money reported in the Statements are currently being expressed in U. S. dollars, the U. S. dollar may therefore be described as the unit of account of the United States. The word dollar is one of the words in the first paragraph of Section 9 of Article I of the Constitution, there, dollars is a reference to the Spanish milled dollar, a coin that had a monetary value of 8 Spanish units of currency, or reales. In 1792 the U. S. Congress passed a Coinage Act, Section 20 of the act provided, That the money of account of the United States shall be expressed in dollars, or units. And that all accounts in the offices and all proceedings in the courts of the United States shall be kept and had in conformity to this regulation. In other words, this act designated the United States dollar as the unit of currency of the United States, unlike the Spanish milled dollar the U. S. dollar is based upon a decimal system of values. Both one-dollar coins and notes are produced today, although the form is significantly more common

9.
Boeing T-43
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The Boeing T-43 was a modified Boeing 737-200 used by the United States Air Force for training navigators, now known in USAF as combat systems officers. Informally referred to as the Gator and Flying Classroom, nineteen of these aircraft were delivered to the Air Training Command at Mather AFB, California during 1973 and 1974. Two T-43s were later converted to CT-43As in the early 1990s and transferred to Air Mobility Command and United States Air Forces in Europe, respectively, as executive transports. A third aircraft was transferred to Air Force Material Command for use as a radar test bed aircraft and was redesignated as an NT-43A. The T-43 was retired by the Air Education and Training Command in 2010 after 37 years of service, the Boeing aircraft was selected in preference to a trainer based on the Douglas DC-9. From its entry into service in 1974 until the mid-1990s, the T-43As were used for all USAF Undergraduate Navigator Training, starting in the mid-1990s, the T-43As were used for USAF Undergraduate Navigator/Combat Systems Officer training with the exception of those USAF Navigators/CSOs slated for the F-15E and B-1B). Navy as the NAV pipeline for training Student Naval Flight Officers slated for eventual assignment to land-based naval aircraft, externally, the T-43 differs from the civilian aircraft by having more antennas and fewer windows. The T-43A had stations on board for twelve students, six navigator instructors. The student training compartment was equipped with avionics gear as used in operational aircraft. Five periscopic sextant stations spaced along the length of the compartment were used for celestial navigation training. However, with the advent of GPS, student navigators were no longer taught celestial navigation or LORAN, the aircraft had considerably more training capability than the aircraft it replaced, the T-29. VT-29 had been training student Naval Flight Officers for various land-based naval aircraft such as the P-3 Orion, EP-3 Aries, and variants of the Lockheed C-130 Hercules. The Navy then merged its Student NFO NAV pipeline with the Air Forces UNT program in 1976, inside each T-43A training compartment were two minimum proficiency, two maximum proficiency and 12 student navigator stations. Two stations form a console, and instructors could move their seats to the consoles, the large cabin allowed easy access to seating and storage, yet reduces the distance between student stations and instructor positions. S. The two additional aircraft used for air navigation training of USAF Academy cadets continue to be operated by the Colorado Air National Guard at Buckley AFB and Peterson AFB. The 6 AMWs CT-43A aircraft was replaced by a Gulfstream C-37A aircraft in early 2001, throughout its service in the Air Training Command and the successor Air Education and Training Command, no T-43 was ever lost in a mishap. S. Secretary of Commerce Ron Brown and 34 other passengers, there were no survivors and subsequent investigation determined that this was a controlled flight into terrain mishap as a result of pilot error. On 17 September 2010, the last T-43 flight was flown at Randolph Air Force Base, T-43A Model 737-253 powered by two JT8D-9 engines and provision for 3 instructors and 16 student navigators,19 built

10.
Boeing 737 Classic
–
The Boeing 737 Classic is the -300/-400/-500 series of the Boeing 737, so named following the introduction of the -600/-700/-800/-900 series. They are short- to medium-range, narrow-body jet airliners produced by Boeing Commercial Airplanes, the Classic series was introduced as the new generation of the 737. Produced from 1984 to 2000,1,988 aircraft were delivered, development began in 1979, and in 1980 preliminary aircraft specifications were released at the Farnborough Airshow. In March 1981, USAir and Southwest Airlines each ordered 10 aircraft, the wing incorporated a number of changes for improved aerodynamics. The wing tip was extended 9 inches, the leading-edge slats and trailing-edge flaps were adjusted. The flight deck was improved with the optional EFIS, and the passenger cabin incorporated improvements similar to those on the Boeing 757, Boeing selected the CFM56-3 to exclusively power the 737-300 variant. The 737 wings were closer to the ground than previous applications for the CFM56, the overall thrust was also reduced, from 24,000 to 20,000 lbf, mostly due to the reduction in bypass ratio. The prototype of the -300 rolled out of the Renton plant on January 17,1984, after it received its flight certification on November 14,1984, USAir received the first aircraft on November 28. A very popular aircraft, Boeing received 252 orders for it in 1985, the 300 series remained in production until 1999 when the last aircraft was delivered to Air New Zealand on December 17,1999, registration ZK-NGJ. The 737-300 can be retrofitted with Aviation Partners Boeing winglets, the 737-300 retrofitted with winglets is designated the -300SP. Used passenger -300 aircraft have also converted to freighter versions. The 737-300 has been replaced by the 737-700 in the Boeing 737 Next Generation family, the 737-400 design was launched in 1985 to fill the gap between the 737-300 and the 757-200, and competed with the Airbus A320 and McDonnell Douglas MD-80. It stretched the 737-300 another 10 ft to carry up to 188 passengers and it included a tail bumper to prevent tailscrapes during take-off, and a strengthened wing spar. The prototype rolled out on January 26,1988, and flew for the first time on 19 February 1988, the aircraft entered service on September 15,1988, with launch customer Piedmont Airlines. The 737-400F was not a model delivered by Boeing, but a 737-400 converted to freighter, the Boeing 737-400 never included winglets as an option, just like the Boeing 737-600. Alaska Airlines was the first to one of their 400s from regular service to an aircraft with the ability to handle ten pallets. The airline has also converted five more into fixed combi aircraft for half passenger and these 737-400 Combi aircraft are now in service. The 737-400 was replaced by the 737-800 in the Boeing 737 Next Generation family, the fuselage length of the -500 is 1 ft 7 in longer than the 737-200, accommodating up to 140 passengers

11.
Boeing 737 Next Generation
–
The Boeing 737 Next Generation, commonly abbreviated as 737NG, is the name given to the −600/-700/-800/-900 series of the Boeing 737 airliner. It is the third derivative of the 737, and follows the 737 Classic series. They are short- to medium-range, narrow-body jet airliners, produced since 1996 by Boeing Commercial Airplanes, the 737NG series includes four variants and can seat between 110 and 210 passengers. As of December 2016, a total of 7,071 737NG aircraft have been ordered, the remaining orders are in the -700, -700 BBJ, -800, and -900ER variants. The 737NGs primary competition is with the Airbus A320 family, upgraded and re-engined models in development as the 737 MAX series are to eventually supplant the 737NG, with the first 737 MAX to be delivered in 2017. Prompted by the development of the Airbus A320, which incorporated ground-breaking technologies such as fly-by-wire, after working with potential customers, the 737 Next Generation program was announced on November 17,1993. The 737NG encompasses the −600, −700, −800 and −900 variants, the performance of the 737NG is essentially that of a new airplane, but important commonality is retained from previous 737 generations. The wing was modified, increasing its area by 25% and span by 16 ft, new quieter and more fuel-efficient CFM56-7B engines were used. These improvements combine to increase the 737s range by 900 nmi, a flight test program was operated by 10 aircraft,3 -600s,4 -700s, and 3 -800s. The interior of the 737 Next Generation also became the interior on the Boeing 757-300. In 2010, the interior of the 737 Next Generation was updated to look similar to that of the Boeing 787, known as the Boeing Sky Interior, it introduces new pivoting overhead bins, new sidewalls, new passenger service units, and LED mood lighting. Boeing also offers BSI retrofits for older 737NG aircraft, Boeings Space Bins carry 50% more than the pivoting bins, allowing a 737 to hold 174 carry-on bags. The first NG to roll out was a −700, on December 8,1996 and this aircraft, the 2, 843rd 737 built, first flew on February 9,1997 with pilots Mike Hewett and Ken Higgins. The prototype −800 rolled out on June 30,1997 and first flew on July 31,1997, piloted by Jim McRoberts, the monthly production rate could reach 57 per month in 2019, even to the factory limit of 63 later. A single airplane is produced in Boeing Renton Factory in 10 days, the empty fuselage from Spirit AeroSystems in Wichita, Kansas, enters the plant on Day 1. Electrical wiring is installed on Day 2 and hydraulic machinery on Day 3, on Day 4 the fuselage is crane-lifted and rotated 90 degrees, wings are mated to the airplane in a six-hour process, along with landing gear, and the airplane is again rotated 90 degrees. The final assembly process begins on Day 6 with the installation of seats, galleys, lavatories, overhead bins. Engines are attached on Day 8 and it rolls out of the factory for test flights on Day 10

Rolls-Royce Conway low bypass turbofan from a Boeing 707. The bypass air exits from the fins whilst the exhaust from the core exits from the central nozzle. This fluted jetpipe design is a noise-reducing method devised by Frederick Greatorex at Rolls-Royce